912 excessive RPM drop on lane A

The new module will allow you to start on it which has the soft start built in and then bring on the older module after the start. So it will end up being an upgrade, which will protect the spraq clutch and starter from damage caused by kickbacks of a failed start.

Upgrading to the latest ignition module might seem desirable, but it is NOT a Drop-In Affair.

It will require considerable modification to the Engines wiring harness.

The 4-pin connector will need to be replaced with a 6-pin connector and the existing 6-pin connector will also need to be replaced because the 6-pin connectors on the new module will be of the opposite gender to prevent the accidental installation of the improper module.  It just won't connect!

It can be done, but it will not be a 30-minute job.

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I would love to see the results of that dual timing light test.

It would be a lot cheaper than buying an ignition module that you might not need.

I will bet that you can borrow a couple of timing lights from some local mechanics and they might not even want them back.   I have one that I haven't used in 30+ years.

Harbor freight $30. Craigslist $10.

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Don't worry about us giving up on you.

We love the challenge and don't mind sharing your grief. 

We won't quit if you don't!

I just talked to the guy who sent me the carburetor and he’s got an old set of modules that came out of a working 912. In case it’s not carbs we will try replacing modules.

Good for you! You are almost done with this problem.

Robert Ovenstone wrote:

Once I locate the problem if it turns out to be a bad module I’m going to try the timing trick before I fix it. Then I’ll know what I’m looking for if it happens to me again or if I’m helping somebody else with a problem.

That would be excellent!

It should be possible to actually photograph the strobe effect to show the Blade split.

If you could do this you would be the first person to visualize a dual plug ignition.

You might become famous and win a Noble prize... Or Not !!!  

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On a more serious note...

I have been trying to think of a way that a non-SoftStart Module might fail and produce the SoftStart timing.

As the timing cam passes the Trigger coil, it produces two pulses; One on the leading edge and one on the trailing edge.

Normal timing occurs on the Leading edge of the timing cam.

SoftStart Timing occurs on the Trailing edge.

Not knowing the circuit within the module, I can imagine that the failure of something as simple as a single diode could reverse the polarity of the pulses.  It is at least a possibility.

This is really an interesting problem!!!